True, but in this case I found it's better to build Settlers when recovering after previous whips, while working max. seafood, which brings lots of commerce as well.
The point is to work max commerce. If you build Granaries etc. not by whipping, you have to work mines rather than seafood, only the mines do not generate commerce. 3 seafood = 6 commerce (1 gold mine = 7 commerce.)
So, max commerce from seafood, please, but don't grow into unhappiness.
Another point is, you can convert food into hammers by whipping at a better rate than directly converting food->hammers by building Settlers, only if you have moderate amount of food. If you have excessive amount of food, you will have to switch to mines at some point, since you have happiness cap, which is not very high. You grow too fast, so you can't take advantage of all that food, you simply lose much of it, this way annihilating all hammer benefits from whipping. But if you build Settlers directly from that food, you can use it infinitely.
After Bureaucracy things change, whips add +50% hammers, so whip a Settler as well, then switch to Caste right away, and max food + specialists rather than mines.